This afternoon (with no changes made by me) ffxiv has become unplayable on DirectX 11 unless I mute the game entirely.
If I unmute it I instantly get this error:
"An unexpected error has occurred. Exiting Final Fantasy XIV. 2019-04-15_18:12

XAudio2_7.dll+34C29
XAudio2_7.dll+2FF91
XAudio2_7.dll+2B4B3
XAudio2_7.dll+2A917
ffxiv_dx11.exe+11E8C1E
ffxiv_dx11.exe+11CB8EC
ffxiv_dx11.exe+11BC318
ffxiv_dx11.exe+13F21A0"
and the game closes, if it is unmuted when it loads up it either crashes on the start menu or has no audio.

The game ran without issue this morning after the update.

The issue does not occur on DirectX 9